This invention relates to a boot and especially to a boot suited for sports such as skiing. More particularly, it relates to a boot having water-proofness and air permeability, and comprising a thicker outer sheath formed of impermeable material such as synthetic resin material.
Boots comprised of a substrate formed of soft and pliable material such as natural or synthetic leather in the shape of a boot, and an outer sheath formed of synthetic resin material and applied to the outside of the substrate, and boots formed of single layer of synthetic resin material without such boot-shaped substrate provided are known in the art. Especially, ski boots or other kinds of sport boots comprised of such air permeable substrate of soft material such as natural or synthetic leather and an outer sheath of synthetic material applied to the outside of the substrate have been proposed for reducing the manufacturing costs and heightening the durability, abrasion resistancy, air-tightness, heat retaining property and stability of the boots.
Such known boots are excellent in durability, abrasion resistance, water-proofness, heat retaining property, stability and protection of the users' feet, since the outer side of the substrate is covered with the outer sheath of synthetic resin material. However, there is a shortcoming with such boots in that the users' feet may sweat on account of poor air permeability, giving rise to a bad sweating odor.
The present invention, with a view to solving such shortcoming and inconvenience as mentioned above, has made an invention entitled "BOOT" as disclosed in Japanese patent Publication No. 60-58841, being a boot which is comprised of an air permeable boot-shaped substrate made of soft and pliable material, an outer sheath made of synthetic resin material applied in situ to the outside of said substrate, air permeable means provided in suitable portions of the sole part of said outer sheath and having ventilation through-holes providing ventilation between the inside and outside of said outer sheath, and water-proof air permeable layers of porous synthetic material provided at least to portions corresponding to said ventilation through-holes in said air permeable means between said substrate and said outer sheath, thus providing air permeablity for the boot, while retaining excellent characteristics such as good durability, abrasion resistance, air-tightness, heat retention, safety and protection of the users' feet. There is, however, a possibility of such air permeable means dropping off the boot on account of a bend or flexure that may be caused thereto when subjected to hard use. Particularly with a ski boot, in case of snow entering the boot through the mouth thereof, there arises another problem of condensation forming on the inner side of the outer sheath on account of the differential between lower atmospheric temperature and higher temperature inside the boot, giving the users an uncomfortable feeling of chilliness in their feet. It is difficult to prevent such condensation with such air permeable means.
Moreover, in cases where a water-proof air permeable layer is provided between the substrate and the outer sheath, an opening or space is then formed between said layer and the air permeable means, causing a risk of water entering the boot through such opening or space.
It is also noticed that a sport boot such as ski boot the sole of which is almost continuously pressed on the ground or snow and which has air permeable means in the sole part of the outer sheath, have further shortcomings such as insufficient water-proofness and poor heat retention in the possible case of water entering the boots through the ventilation through-holes in the air permeable means.